U.S. Pat. No. 4,663,725, which is assigned to the same assignee as the present application, discloses the use of microprocessor based transport refrigeration control for use with a refrigerated container, with the refrigerant compressor being driven by an electric motor. This patent is directed primarily to the use of a microprocessor to operate the various components of the refrigeration system according to predetermined algorithms, and to detect and record faults which occur during the operation thereof.
U.S. Pat. No. 4,918,932, which is assigned to the same assignee as the present application, discloses the use of a microprocessor to determine average error between an operator selected set point temperature and the temperature of a space to be conditioned, using the outputs of return air and discharge air sensors. The average error is then used in the determination of an error signal which modulates the capacity of the system.
While these patents ably utilize the capabilities of a microprocessor in controlling the operation of a transport refrigeration system, it would be desirable, and it is an object of the present invention, to expand the use of the microprocessor which controls the unit to provide additional services related to maintenance of the transport refrigeration system.